1 /* Global constant/copy propagation for RTL.
2 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
3 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
25 #include "diagnostic-core.h"
32 #include "hard-reg-set.h"
34 #include "insn-config.h"
36 #include "basic-block.h"
46 #include "tree-pass.h"
53 /* An obstack for our working variables. */
54 static struct obstack cprop_obstack;
56 /* Occurrence of an expression.
57 There is one per basic block. If a pattern appears more than once the
58 last appearance is used. */
62 /* Next occurrence of this expression. */
64 /* The insn that computes the expression. */
68 typedef struct occr *occr_t;
70 DEF_VEC_ALLOC_P (occr_t, heap);
72 /* Hash table entry for assignment expressions. */
76 /* The expression (DEST := SRC). */
80 /* Index in the available expression bitmaps. */
82 /* Next entry with the same hash. */
83 struct expr *next_same_hash;
84 /* List of available occurrence in basic blocks in the function.
85 An "available occurrence" is one that is the last occurrence in the
86 basic block and whose operands are not modified by following statements
87 in the basic block [including this insn]. */
88 struct occr *avail_occr;
91 /* Hash table for copy propagation expressions.
92 Each hash table is an array of buckets.
93 ??? It is known that if it were an array of entries, structure elements
94 `next_same_hash' and `bitmap_index' wouldn't be necessary. However, it is
95 not clear whether in the final analysis a sufficient amount of memory would
96 be saved as the size of the available expression bitmaps would be larger
97 [one could build a mapping table without holes afterwards though].
98 Someday I'll perform the computation and figure it out. */
103 This is an array of `set_hash_table_size' elements. */
106 /* Size of the hash table, in elements. */
109 /* Number of hash table elements. */
110 unsigned int n_elems;
113 /* Copy propagation hash table. */
114 static struct hash_table_d set_hash_table;
116 /* Array of implicit set patterns indexed by basic block index. */
117 static rtx *implicit_sets;
119 /* Bitmap containing one bit for each register in the program.
120 Used when performing GCSE to track which registers have been set since
121 the start or end of the basic block while traversing that block. */
122 static regset reg_set_bitmap;
124 /* Various variables for statistics gathering. */
126 /* Memory used in a pass.
127 This isn't intended to be absolutely precise. Its intent is only
128 to keep an eye on memory usage. */
129 static int bytes_used;
131 /* Number of local constants propagated. */
132 static int local_const_prop_count;
133 /* Number of local copies propagated. */
134 static int local_copy_prop_count;
135 /* Number of global constants propagated. */
136 static int global_const_prop_count;
137 /* Number of global copies propagated. */
138 static int global_copy_prop_count;
140 #define GOBNEW(T) ((T *) cprop_alloc (sizeof (T)))
141 #define GOBNEWVAR(T, S) ((T *) cprop_alloc ((S)))
143 /* Cover function to obstack_alloc. */
146 cprop_alloc (unsigned long size)
149 return obstack_alloc (&cprop_obstack, size);
152 /* Return nonzero if register X is unchanged from INSN to the end
153 of INSN's basic block. */
156 reg_available_p (const_rtx x, const_rtx insn ATTRIBUTE_UNUSED)
158 return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
161 /* Hash a set of register REGNO.
163 Sets are hashed on the register that is set. This simplifies the PRE copy
166 ??? May need to make things more elaborate. Later, as necessary. */
169 hash_set (int regno, int hash_table_size)
174 return hash % hash_table_size;
177 /* Insert assignment DEST:=SET from INSN in the hash table.
178 DEST is a register and SET is a register or a suitable constant.
179 If the assignment is already present in the table, record it as
180 the last occurrence in INSN's basic block. */
183 insert_set_in_table (rtx dest, rtx src, rtx insn, struct hash_table_d *table)
187 struct expr *cur_expr, *last_expr = NULL;
188 struct occr *cur_occr;
190 hash = hash_set (REGNO (dest), table->size);
192 for (cur_expr = table->table[hash]; cur_expr;
193 cur_expr = cur_expr->next_same_hash)
195 if (dest == cur_expr->dest
196 && src == cur_expr->src)
201 last_expr = cur_expr;
206 cur_expr = GOBNEW (struct expr);
207 bytes_used += sizeof (struct expr);
208 if (table->table[hash] == NULL)
209 /* This is the first pattern that hashed to this index. */
210 table->table[hash] = cur_expr;
212 /* Add EXPR to end of this hash chain. */
213 last_expr->next_same_hash = cur_expr;
215 /* Set the fields of the expr element.
216 We must copy X because it can be modified when copy propagation is
217 performed on its operands. */
218 cur_expr->dest = copy_rtx (dest);
219 cur_expr->src = copy_rtx (src);
220 cur_expr->bitmap_index = table->n_elems++;
221 cur_expr->next_same_hash = NULL;
222 cur_expr->avail_occr = NULL;
225 /* Now record the occurrence. */
226 cur_occr = cur_expr->avail_occr;
229 && BLOCK_FOR_INSN (cur_occr->insn) == BLOCK_FOR_INSN (insn))
231 /* Found another instance of the expression in the same basic block.
232 Prefer this occurrence to the currently recorded one. We want
233 the last one in the block and the block is scanned from start
235 cur_occr->insn = insn;
239 /* First occurrence of this expression in this basic block. */
240 cur_occr = GOBNEW (struct occr);
241 bytes_used += sizeof (struct occr);
242 cur_occr->insn = insn;
243 cur_occr->next = cur_expr->avail_occr;
244 cur_expr->avail_occr = cur_occr;
248 /* Determine whether the rtx X should be treated as a constant for CPROP.
249 Since X might be inserted more than once we have to take care that it
253 cprop_constant_p (const_rtx x)
255 return CONSTANT_P (x) && (GET_CODE (x) != CONST || shared_const_p (x));
258 /* Scan SET present in INSN and add an entry to the hash TABLE. */
261 hash_scan_set (rtx set, rtx insn, struct hash_table_d *table)
263 rtx src = SET_SRC (set);
264 rtx dest = SET_DEST (set);
267 && ! HARD_REGISTER_P (dest)
268 && reg_available_p (dest, insn)
269 && can_copy_p (GET_MODE (dest)))
271 /* See if a REG_EQUAL note shows this equivalent to a simpler expression.
273 This allows us to do a single CPROP pass and still eliminate
274 redundant constants, addresses or other expressions that are
275 constructed with multiple instructions.
277 However, keep the original SRC if INSN is a simple reg-reg move. In
278 In this case, there will almost always be a REG_EQUAL note on the
279 insn that sets SRC. By recording the REG_EQUAL value here as SRC
280 for INSN, we miss copy propagation opportunities.
282 Note that this does not impede profitable constant propagations. We
283 "look through" reg-reg sets in lookup_set. */
284 rtx note = find_reg_equal_equiv_note (insn);
286 && REG_NOTE_KIND (note) == REG_EQUAL
288 && cprop_constant_p (XEXP (note, 0)))
289 src = XEXP (note, 0), set = gen_rtx_SET (VOIDmode, dest, src);
291 /* Record sets for constant/copy propagation. */
294 && ! HARD_REGISTER_P (src)
295 && reg_available_p (src, insn))
296 || cprop_constant_p (src))
297 insert_set_in_table (dest, src, insn, table);
301 /* Process INSN and add hash table entries as appropriate. */
304 hash_scan_insn (rtx insn, struct hash_table_d *table)
306 rtx pat = PATTERN (insn);
309 /* Pick out the sets of INSN and for other forms of instructions record
310 what's been modified. */
312 if (GET_CODE (pat) == SET)
313 hash_scan_set (pat, insn, table);
314 else if (GET_CODE (pat) == PARALLEL)
315 for (i = 0; i < XVECLEN (pat, 0); i++)
317 rtx x = XVECEXP (pat, 0, i);
319 if (GET_CODE (x) == SET)
320 hash_scan_set (x, insn, table);
324 /* Dump the hash table TABLE to file FILE under the name NAME. */
327 dump_hash_table (FILE *file, const char *name, struct hash_table_d *table)
330 /* Flattened out table, so it's printed in proper order. */
331 struct expr **flat_table;
332 unsigned int *hash_val;
335 flat_table = XCNEWVEC (struct expr *, table->n_elems);
336 hash_val = XNEWVEC (unsigned int, table->n_elems);
338 for (i = 0; i < (int) table->size; i++)
339 for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
341 flat_table[expr->bitmap_index] = expr;
342 hash_val[expr->bitmap_index] = i;
345 fprintf (file, "%s hash table (%d buckets, %d entries)\n",
346 name, table->size, table->n_elems);
348 for (i = 0; i < (int) table->n_elems; i++)
349 if (flat_table[i] != 0)
351 expr = flat_table[i];
352 fprintf (file, "Index %d (hash value %d)\n ",
353 expr->bitmap_index, hash_val[i]);
354 print_rtl (file, expr->dest);
355 fprintf (file, " := ");
356 print_rtl (file, expr->src);
357 fprintf (file, "\n");
360 fprintf (file, "\n");
366 /* Record as unavailable all registers that are DEF operands of INSN. */
369 make_set_regs_unavailable (rtx insn)
371 struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
374 for (def_rec = DF_INSN_INFO_DEFS (insn_info); *def_rec; def_rec++)
375 SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (*def_rec));
378 /* Top level function to create an assignment hash table.
380 Assignment entries are placed in the hash table if
381 - they are of the form (set (pseudo-reg) src),
382 - src is something we want to perform const/copy propagation on,
383 - none of the operands or target are subsequently modified in the block
385 Currently src must be a pseudo-reg or a const_int.
387 TABLE is the table computed. */
390 compute_hash_table_work (struct hash_table_d *table)
394 /* Allocate vars to track sets of regs. */
395 reg_set_bitmap = ALLOC_REG_SET (NULL);
401 /* Reset tables used to keep track of what's not yet invalid [since
402 the end of the block]. */
403 CLEAR_REG_SET (reg_set_bitmap);
405 /* Go over all insns from the last to the first. This is convenient
406 for tracking available registers, i.e. not set between INSN and
407 the end of the basic block BB. */
408 FOR_BB_INSNS_REVERSE (bb, insn)
410 /* Only real insns are interesting. */
411 if (!NONDEBUG_INSN_P (insn))
414 /* Record interesting sets from INSN in the hash table. */
415 hash_scan_insn (insn, table);
417 /* Any registers set in INSN will make SETs above it not AVAIL. */
418 make_set_regs_unavailable (insn);
421 /* Insert implicit sets in the hash table, pretending they appear as
422 insns at the head of the basic block. */
423 if (implicit_sets[bb->index] != NULL_RTX)
424 hash_scan_set (implicit_sets[bb->index], BB_HEAD (bb), table);
427 FREE_REG_SET (reg_set_bitmap);
430 /* Allocate space for the set/expr hash TABLE.
431 It is used to determine the number of buckets to use. */
434 alloc_hash_table (struct hash_table_d *table)
438 n = get_max_insn_count ();
441 if (table->size < 11)
444 /* Attempt to maintain efficient use of hash table.
445 Making it an odd number is simplest for now.
446 ??? Later take some measurements. */
448 n = table->size * sizeof (struct expr *);
449 table->table = XNEWVAR (struct expr *, n);
452 /* Free things allocated by alloc_hash_table. */
455 free_hash_table (struct hash_table_d *table)
460 /* Compute the hash TABLE for doing copy/const propagation or
461 expression hash table. */
464 compute_hash_table (struct hash_table_d *table)
466 /* Initialize count of number of entries in hash table. */
468 memset (table->table, 0, table->size * sizeof (struct expr *));
470 compute_hash_table_work (table);
473 /* Expression tracking support. */
475 /* Lookup REGNO in the set TABLE. The result is a pointer to the
476 table entry, or NULL if not found. */
479 lookup_set (unsigned int regno, struct hash_table_d *table)
481 unsigned int hash = hash_set (regno, table->size);
484 expr = table->table[hash];
486 while (expr && REGNO (expr->dest) != regno)
487 expr = expr->next_same_hash;
492 /* Return the next entry for REGNO in list EXPR. */
495 next_set (unsigned int regno, struct expr *expr)
498 expr = expr->next_same_hash;
499 while (expr && REGNO (expr->dest) != regno);
504 /* Reset tables used to keep track of what's still available [since the
505 start of the block]. */
508 reset_opr_set_tables (void)
510 /* Maintain a bitmap of which regs have been set since beginning of
512 CLEAR_REG_SET (reg_set_bitmap);
515 /* Return nonzero if the register X has not been set yet [since the
516 start of the basic block containing INSN]. */
519 reg_not_set_p (const_rtx x, const_rtx insn ATTRIBUTE_UNUSED)
521 return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
524 /* Record things set by INSN.
525 This data is used by reg_not_set_p. */
528 mark_oprs_set (rtx insn)
530 struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
533 for (def_rec = DF_INSN_INFO_DEFS (insn_info); *def_rec; def_rec++)
534 SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (*def_rec));
537 /* Compute copy/constant propagation working variables. */
539 /* Local properties of assignments. */
540 static sbitmap *cprop_avloc;
541 static sbitmap *cprop_kill;
543 /* Global properties of assignments (computed from the local properties). */
544 static sbitmap *cprop_avin;
545 static sbitmap *cprop_avout;
547 /* Allocate vars used for copy/const propagation. N_BLOCKS is the number of
548 basic blocks. N_SETS is the number of sets. */
551 alloc_cprop_mem (int n_blocks, int n_sets)
553 cprop_avloc = sbitmap_vector_alloc (n_blocks, n_sets);
554 cprop_kill = sbitmap_vector_alloc (n_blocks, n_sets);
556 cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets);
557 cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets);
560 /* Free vars used by copy/const propagation. */
563 free_cprop_mem (void)
565 sbitmap_vector_free (cprop_avloc);
566 sbitmap_vector_free (cprop_kill);
567 sbitmap_vector_free (cprop_avin);
568 sbitmap_vector_free (cprop_avout);
571 /* Compute the local properties of each recorded expression.
573 Local properties are those that are defined by the block, irrespective of
576 An expression is killed in a block if its operands, either DEST or SRC, are
577 modified in the block.
579 An expression is computed (locally available) in a block if it is computed
580 at least once and expression would contain the same value if the
581 computation was moved to the end of the block.
583 KILL and COMP are destination sbitmaps for recording local properties. */
586 compute_local_properties (sbitmap *kill, sbitmap *comp,
587 struct hash_table_d *table)
591 /* Initialize the bitmaps that were passed in. */
592 sbitmap_vector_zero (kill, last_basic_block);
593 sbitmap_vector_zero (comp, last_basic_block);
595 for (i = 0; i < table->size; i++)
599 for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
601 int indx = expr->bitmap_index;
605 /* For each definition of the destination pseudo-reg, the expression
606 is killed in the block where the definition is. */
607 for (def = DF_REG_DEF_CHAIN (REGNO (expr->dest));
608 def; def = DF_REF_NEXT_REG (def))
609 SET_BIT (kill[DF_REF_BB (def)->index], indx);
611 /* If the source is a pseudo-reg, for each definition of the source,
612 the expression is killed in the block where the definition is. */
613 if (REG_P (expr->src))
614 for (def = DF_REG_DEF_CHAIN (REGNO (expr->src));
615 def; def = DF_REF_NEXT_REG (def))
616 SET_BIT (kill[DF_REF_BB (def)->index], indx);
618 /* The occurrences recorded in avail_occr are exactly those that
619 are locally available in the block where they are. */
620 for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
622 SET_BIT (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
628 /* Hash table support. */
630 /* Top level routine to do the dataflow analysis needed by copy/const
634 compute_cprop_data (void)
636 compute_local_properties (cprop_kill, cprop_avloc, &set_hash_table);
637 compute_available (cprop_avloc, cprop_kill, cprop_avout, cprop_avin);
640 /* Copy/constant propagation. */
642 /* Maximum number of register uses in an insn that we handle. */
645 /* Table of uses (registers, both hard and pseudo) found in an insn.
646 Allocated statically to avoid alloc/free complexity and overhead. */
647 static rtx reg_use_table[MAX_USES];
649 /* Index into `reg_use_table' while building it. */
650 static unsigned reg_use_count;
652 /* Set up a list of register numbers used in INSN. The found uses are stored
653 in `reg_use_table'. `reg_use_count' is initialized to zero before entry,
654 and contains the number of uses in the table upon exit.
656 ??? If a register appears multiple times we will record it multiple times.
657 This doesn't hurt anything but it will slow things down. */
660 find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED)
667 /* repeat is used to turn tail-recursion into iteration since GCC
668 can't do it when there's no return value. */
676 if (reg_use_count == MAX_USES)
679 reg_use_table[reg_use_count] = x;
683 /* Recursively scan the operands of this expression. */
685 for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
689 /* If we are about to do the last recursive call
690 needed at this level, change it into iteration.
691 This function is called enough to be worth it. */
698 find_used_regs (&XEXP (x, i), data);
700 else if (fmt[i] == 'E')
701 for (j = 0; j < XVECLEN (x, i); j++)
702 find_used_regs (&XVECEXP (x, i, j), data);
706 /* Try to replace all uses of FROM in INSN with TO.
707 Return nonzero if successful. */
710 try_replace_reg (rtx from, rtx to, rtx insn)
712 rtx note = find_reg_equal_equiv_note (insn);
715 rtx set = single_set (insn);
717 /* Usually we substitute easy stuff, so we won't copy everything.
718 We however need to take care to not duplicate non-trivial CONST
722 validate_replace_src_group (from, to, insn);
723 if (num_changes_pending () && apply_change_group ())
726 /* Try to simplify SET_SRC if we have substituted a constant. */
727 if (success && set && CONSTANT_P (to))
729 src = simplify_rtx (SET_SRC (set));
732 validate_change (insn, &SET_SRC (set), src, 0);
735 /* If there is already a REG_EQUAL note, update the expression in it
736 with our replacement. */
737 if (note != 0 && REG_NOTE_KIND (note) == REG_EQUAL)
738 set_unique_reg_note (insn, REG_EQUAL,
739 simplify_replace_rtx (XEXP (note, 0), from, to));
740 if (!success && set && reg_mentioned_p (from, SET_SRC (set)))
742 /* If above failed and this is a single set, try to simplify the source
743 of the set given our substitution. We could perhaps try this for
744 multiple SETs, but it probably won't buy us anything. */
745 src = simplify_replace_rtx (SET_SRC (set), from, to);
747 if (!rtx_equal_p (src, SET_SRC (set))
748 && validate_change (insn, &SET_SRC (set), src, 0))
751 /* If we've failed perform the replacement, have a single SET to
752 a REG destination and don't yet have a note, add a REG_EQUAL note
753 to not lose information. */
754 if (!success && note == 0 && set != 0 && REG_P (SET_DEST (set)))
755 note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
758 if (set && MEM_P (SET_DEST (set)) && reg_mentioned_p (from, SET_DEST (set)))
760 /* Registers can also appear as uses in SET_DEST if it is a MEM.
761 We could perhaps try this for multiple SETs, but it probably
762 won't buy us anything. */
763 rtx dest = simplify_replace_rtx (SET_DEST (set), from, to);
765 if (!rtx_equal_p (dest, SET_DEST (set))
766 && validate_change (insn, &SET_DEST (set), dest, 0))
770 /* REG_EQUAL may get simplified into register.
771 We don't allow that. Remove that note. This code ought
772 not to happen, because previous code ought to synthesize
773 reg-reg move, but be on the safe side. */
774 if (note && REG_NOTE_KIND (note) == REG_EQUAL && REG_P (XEXP (note, 0)))
775 remove_note (insn, note);
780 /* Find a set of REGNOs that are available on entry to INSN's block. Return
781 NULL no such set is found. */
784 find_avail_set (int regno, rtx insn)
786 /* SET1 contains the last set found that can be returned to the caller for
787 use in a substitution. */
788 struct expr *set1 = 0;
790 /* Loops are not possible here. To get a loop we would need two sets
791 available at the start of the block containing INSN. i.e. we would
792 need two sets like this available at the start of the block:
794 (set (reg X) (reg Y))
795 (set (reg Y) (reg X))
797 This can not happen since the set of (reg Y) would have killed the
798 set of (reg X) making it unavailable at the start of this block. */
802 struct expr *set = lookup_set (regno, &set_hash_table);
804 /* Find a set that is available at the start of the block
805 which contains INSN. */
808 if (TEST_BIT (cprop_avin[BLOCK_FOR_INSN (insn)->index],
811 set = next_set (regno, set);
814 /* If no available set was found we've reached the end of the
815 (possibly empty) copy chain. */
821 /* We know the set is available.
822 Now check that SRC is locally anticipatable (i.e. none of the
823 source operands have changed since the start of the block).
825 If the source operand changed, we may still use it for the next
826 iteration of this loop, but we may not use it for substitutions. */
828 if (cprop_constant_p (src) || reg_not_set_p (src, insn))
831 /* If the source of the set is anything except a register, then
832 we have reached the end of the copy chain. */
836 /* Follow the copy chain, i.e. start another iteration of the loop
837 and see if we have an available copy into SRC. */
841 /* SET1 holds the last set that was available and anticipatable at
846 /* Subroutine of cprop_insn that tries to propagate constants into
847 JUMP_INSNS. JUMP must be a conditional jump. If SETCC is non-NULL
848 it is the instruction that immediately precedes JUMP, and must be a
849 single SET of a register. FROM is what we will try to replace,
850 SRC is the constant we will try to substitute for it. Return nonzero
851 if a change was made. */
854 cprop_jump (basic_block bb, rtx setcc, rtx jump, rtx from, rtx src)
856 rtx new_rtx, set_src, note_src;
857 rtx set = pc_set (jump);
858 rtx note = find_reg_equal_equiv_note (jump);
862 note_src = XEXP (note, 0);
863 if (GET_CODE (note_src) == EXPR_LIST)
866 else note_src = NULL_RTX;
868 /* Prefer REG_EQUAL notes except those containing EXPR_LISTs. */
869 set_src = note_src ? note_src : SET_SRC (set);
871 /* First substitute the SETCC condition into the JUMP instruction,
872 then substitute that given values into this expanded JUMP. */
873 if (setcc != NULL_RTX
874 && !modified_between_p (from, setcc, jump)
875 && !modified_between_p (src, setcc, jump))
878 rtx setcc_set = single_set (setcc);
879 rtx setcc_note = find_reg_equal_equiv_note (setcc);
880 setcc_src = (setcc_note && GET_CODE (XEXP (setcc_note, 0)) != EXPR_LIST)
881 ? XEXP (setcc_note, 0) : SET_SRC (setcc_set);
882 set_src = simplify_replace_rtx (set_src, SET_DEST (setcc_set),
888 new_rtx = simplify_replace_rtx (set_src, from, src);
890 /* If no simplification can be made, then try the next register. */
891 if (rtx_equal_p (new_rtx, SET_SRC (set)))
894 /* If this is now a no-op delete it, otherwise this must be a valid insn. */
895 if (new_rtx == pc_rtx)
899 /* Ensure the value computed inside the jump insn to be equivalent
900 to one computed by setcc. */
901 if (setcc && modified_in_p (new_rtx, setcc))
903 if (! validate_unshare_change (jump, &SET_SRC (set), new_rtx, 0))
905 /* When (some) constants are not valid in a comparison, and there
906 are two registers to be replaced by constants before the entire
907 comparison can be folded into a constant, we need to keep
908 intermediate information in REG_EQUAL notes. For targets with
909 separate compare insns, such notes are added by try_replace_reg.
910 When we have a combined compare-and-branch instruction, however,
911 we need to attach a note to the branch itself to make this
912 optimization work. */
914 if (!rtx_equal_p (new_rtx, note_src))
915 set_unique_reg_note (jump, REG_EQUAL, copy_rtx (new_rtx));
919 /* Remove REG_EQUAL note after simplification. */
921 remove_note (jump, note);
925 /* Delete the cc0 setter. */
926 if (setcc != NULL && CC0_P (SET_DEST (single_set (setcc))))
930 global_const_prop_count++;
931 if (dump_file != NULL)
934 "GLOBAL CONST-PROP: Replacing reg %d in jump_insn %d with"
935 "constant ", REGNO (from), INSN_UID (jump));
936 print_rtl (dump_file, src);
937 fprintf (dump_file, "\n");
939 purge_dead_edges (bb);
941 /* If a conditional jump has been changed into unconditional jump, remove
942 the jump and make the edge fallthru - this is always called in
944 if (new_rtx != pc_rtx && simplejump_p (jump))
949 FOR_EACH_EDGE (e, ei, bb->succs)
950 if (e->dest != EXIT_BLOCK_PTR
951 && BB_HEAD (e->dest) == JUMP_LABEL (jump))
953 e->flags |= EDGE_FALLTHRU;
962 /* Subroutine of cprop_insn that tries to propagate constants. FROM is what
963 we will try to replace, SRC is the constant we will try to substitute for
964 it and INSN is the instruction where this will be happening. */
967 constprop_register (rtx from, rtx src, rtx insn)
971 /* Check for reg or cc0 setting instructions followed by
972 conditional branch instructions first. */
973 if ((sset = single_set (insn)) != NULL
975 && any_condjump_p (NEXT_INSN (insn)) && onlyjump_p (NEXT_INSN (insn)))
977 rtx dest = SET_DEST (sset);
978 if ((REG_P (dest) || CC0_P (dest))
979 && cprop_jump (BLOCK_FOR_INSN (insn), insn, NEXT_INSN (insn),
984 /* Handle normal insns next. */
985 if (NONJUMP_INSN_P (insn) && try_replace_reg (from, src, insn))
988 /* Try to propagate a CONST_INT into a conditional jump.
989 We're pretty specific about what we will handle in this
990 code, we can extend this as necessary over time.
992 Right now the insn in question must look like
993 (set (pc) (if_then_else ...)) */
994 else if (any_condjump_p (insn) && onlyjump_p (insn))
995 return cprop_jump (BLOCK_FOR_INSN (insn), NULL, insn, from, src);
999 /* Perform constant and copy propagation on INSN.
1000 Return nonzero if a change was made. */
1003 cprop_insn (rtx insn)
1006 int changed = 0, changed_this_round;
1010 changed_this_round = 0;
1012 note_uses (&PATTERN (insn), find_used_regs, NULL);
1014 /* We may win even when propagating constants into notes. */
1015 note = find_reg_equal_equiv_note (insn);
1017 find_used_regs (&XEXP (note, 0), NULL);
1019 for (i = 0; i < reg_use_count; i++)
1021 rtx reg_used = reg_use_table[i];
1022 unsigned int regno = REGNO (reg_used);
1026 /* If the register has already been set in this block, there's
1027 nothing we can do. */
1028 if (! reg_not_set_p (reg_used, insn))
1031 /* Find an assignment that sets reg_used and is available
1032 at the start of the block. */
1033 set = find_avail_set (regno, insn);
1039 /* Constant propagation. */
1040 if (cprop_constant_p (src))
1042 if (constprop_register (reg_used, src, insn))
1044 changed_this_round = changed = 1;
1045 global_const_prop_count++;
1046 if (dump_file != NULL)
1049 "GLOBAL CONST-PROP: Replacing reg %d in ", regno);
1050 fprintf (dump_file, "insn %d with constant ",
1052 print_rtl (dump_file, src);
1053 fprintf (dump_file, "\n");
1055 if (INSN_DELETED_P (insn))
1059 else if (REG_P (src)
1060 && REGNO (src) >= FIRST_PSEUDO_REGISTER
1061 && REGNO (src) != regno)
1063 if (try_replace_reg (reg_used, src, insn))
1065 changed_this_round = changed = 1;
1066 global_copy_prop_count++;
1067 if (dump_file != NULL)
1070 "GLOBAL COPY-PROP: Replacing reg %d in insn %d",
1071 regno, INSN_UID (insn));
1072 fprintf (dump_file, " with reg %d\n", REGNO (src));
1075 /* The original insn setting reg_used may or may not now be
1076 deletable. We leave the deletion to DCE. */
1077 /* FIXME: If it turns out that the insn isn't deletable,
1078 then we may have unnecessarily extended register lifetimes
1079 and made things worse. */
1083 /* If try_replace_reg simplified the insn, the regs found
1084 by find_used_regs may not be valid anymore. Start over. */
1085 if (changed_this_round)
1089 if (changed && DEBUG_INSN_P (insn))
1095 /* Like find_used_regs, but avoid recording uses that appear in
1096 input-output contexts such as zero_extract or pre_dec. This
1097 restricts the cases we consider to those for which local cprop
1098 can legitimately make replacements. */
1101 local_cprop_find_used_regs (rtx *xptr, void *data)
1108 switch (GET_CODE (x))
1112 case STRICT_LOW_PART:
1121 /* Can only legitimately appear this early in the context of
1122 stack pushes for function arguments, but handle all of the
1123 codes nonetheless. */
1127 /* Setting a subreg of a register larger than word_mode leaves
1128 the non-written words unchanged. */
1129 if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) > BITS_PER_WORD)
1137 find_used_regs (xptr, data);
1140 /* Try to perform local const/copy propagation on X in INSN. */
1143 do_local_cprop (rtx x, rtx insn)
1145 rtx newreg = NULL, newcnst = NULL;
1147 /* Rule out USE instructions and ASM statements as we don't want to
1148 change the hard registers mentioned. */
1150 && (REGNO (x) >= FIRST_PSEUDO_REGISTER
1151 || (GET_CODE (PATTERN (insn)) != USE
1152 && asm_noperands (PATTERN (insn)) < 0)))
1154 cselib_val *val = cselib_lookup (x, GET_MODE (x), 0, VOIDmode);
1155 struct elt_loc_list *l;
1159 for (l = val->locs; l; l = l->next)
1161 rtx this_rtx = l->loc;
1164 if (cprop_constant_p (this_rtx))
1166 if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER
1167 /* Don't copy propagate if it has attached REG_EQUIV note.
1168 At this point this only function parameters should have
1169 REG_EQUIV notes and if the argument slot is used somewhere
1170 explicitly, it means address of parameter has been taken,
1171 so we should not extend the lifetime of the pseudo. */
1172 && (!(note = find_reg_note (l->setting_insn, REG_EQUIV, NULL_RTX))
1173 || ! MEM_P (XEXP (note, 0))))
1176 if (newcnst && constprop_register (x, newcnst, insn))
1178 if (dump_file != NULL)
1180 fprintf (dump_file, "LOCAL CONST-PROP: Replacing reg %d in ",
1182 fprintf (dump_file, "insn %d with constant ",
1184 print_rtl (dump_file, newcnst);
1185 fprintf (dump_file, "\n");
1187 local_const_prop_count++;
1190 else if (newreg && newreg != x && try_replace_reg (x, newreg, insn))
1192 if (dump_file != NULL)
1195 "LOCAL COPY-PROP: Replacing reg %d in insn %d",
1196 REGNO (x), INSN_UID (insn));
1197 fprintf (dump_file, " with reg %d\n", REGNO (newreg));
1199 local_copy_prop_count++;
1206 /* Do local const/copy propagation (i.e. within each basic block). */
1209 local_cprop_pass (void)
1213 bool changed = false;
1219 FOR_BB_INSNS (bb, insn)
1223 rtx note = find_reg_equal_equiv_note (insn);
1227 note_uses (&PATTERN (insn), local_cprop_find_used_regs,
1230 local_cprop_find_used_regs (&XEXP (note, 0), NULL);
1232 for (i = 0; i < reg_use_count; i++)
1234 if (do_local_cprop (reg_use_table[i], insn))
1236 if (!DEBUG_INSN_P (insn))
1241 if (INSN_DELETED_P (insn))
1244 while (i < reg_use_count);
1246 cselib_process_insn (insn);
1249 /* Forget everything at the end of a basic block. */
1250 cselib_clear_table ();
1258 /* Similar to get_condition, only the resulting condition must be
1259 valid at JUMP, instead of at EARLIEST.
1261 This differs from noce_get_condition in ifcvt.c in that we prefer not to
1262 settle for the condition variable in the jump instruction being integral.
1263 We prefer to be able to record the value of a user variable, rather than
1264 the value of a temporary used in a condition. This could be solved by
1265 recording the value of *every* register scanned by canonicalize_condition,
1266 but this would require some code reorganization. */
1269 fis_get_condition (rtx jump)
1271 return get_condition (jump, NULL, false, true);
1274 /* Check the comparison COND to see if we can safely form an implicit
1278 implicit_set_cond_p (const_rtx cond)
1280 enum machine_mode mode;
1283 /* COND must be either an EQ or NE comparison. */
1284 if (GET_CODE (cond) != EQ && GET_CODE (cond) != NE)
1287 /* The first operand of COND must be a pseudo-reg. */
1288 if (! REG_P (XEXP (cond, 0))
1289 || HARD_REGISTER_P (XEXP (cond, 0)))
1292 /* The second operand of COND must be a suitable constant. */
1293 mode = GET_MODE (XEXP (cond, 0));
1294 cst = XEXP (cond, 1);
1296 /* We can't perform this optimization if either operand might be or might
1297 contain a signed zero. */
1298 if (HONOR_SIGNED_ZEROS (mode))
1300 /* It is sufficient to check if CST is or contains a zero. We must
1301 handle float, complex, and vector. If any subpart is a zero, then
1302 the optimization can't be performed. */
1303 /* ??? The complex and vector checks are not implemented yet. We just
1304 always return zero for them. */
1305 if (GET_CODE (cst) == CONST_DOUBLE)
1308 REAL_VALUE_FROM_CONST_DOUBLE (d, cst);
1309 if (REAL_VALUES_EQUAL (d, dconst0))
1316 return cprop_constant_p (cst);
1319 /* Find the implicit sets of a function. An "implicit set" is a constraint
1320 on the value of a variable, implied by a conditional jump. For example,
1321 following "if (x == 2)", the then branch may be optimized as though the
1322 conditional performed an "explicit set", in this example, "x = 2". This
1323 function records the set patterns that are implicit at the start of each
1326 If an implicit set is found but the set is implicit on a critical edge,
1327 this critical edge is split.
1329 Return true if the CFG was modified, false otherwise. */
1332 find_implicit_sets (void)
1334 basic_block bb, dest;
1336 unsigned int count = 0;
1337 bool edges_split = false;
1338 size_t implicit_sets_size = last_basic_block + 10;
1340 implicit_sets = XCNEWVEC (rtx, implicit_sets_size);
1344 /* Check for more than one successor. */
1345 if (EDGE_COUNT (bb->succs) <= 1)
1348 cond = fis_get_condition (BB_END (bb));
1350 /* If no condition is found or if it isn't of a suitable form,
1352 if (! cond || ! implicit_set_cond_p (cond))
1355 dest = GET_CODE (cond) == EQ
1356 ? BRANCH_EDGE (bb)->dest : FALLTHRU_EDGE (bb)->dest;
1358 /* If DEST doesn't go anywhere, ignore it. */
1359 if (! dest || dest == EXIT_BLOCK_PTR)
1362 /* We have found a suitable implicit set. Try to record it now as
1363 a SET in DEST. If DEST has more than one predecessor, the edge
1364 between BB and DEST is a critical edge and we must split it,
1365 because we can only record one implicit set per DEST basic block. */
1366 if (! single_pred_p (dest))
1368 dest = split_edge (find_edge (bb, dest));
1372 if (implicit_sets_size <= (size_t) dest->index)
1374 size_t old_implicit_sets_size = implicit_sets_size;
1375 implicit_sets_size *= 2;
1376 implicit_sets = XRESIZEVEC (rtx, implicit_sets, implicit_sets_size);
1377 memset (implicit_sets + old_implicit_sets_size, 0,
1378 (implicit_sets_size - old_implicit_sets_size) * sizeof (rtx));
1381 new_rtx = gen_rtx_SET (VOIDmode, XEXP (cond, 0),
1383 implicit_sets[dest->index] = new_rtx;
1386 fprintf(dump_file, "Implicit set of reg %d in ",
1387 REGNO (XEXP (cond, 0)));
1388 fprintf(dump_file, "basic block %d\n", dest->index);
1394 fprintf (dump_file, "Found %d implicit sets\n", count);
1396 /* Confess our sins. */
1400 /* Bypass conditional jumps. */
1402 /* The value of last_basic_block at the beginning of the jump_bypass
1403 pass. The use of redirect_edge_and_branch_force may introduce new
1404 basic blocks, but the data flow analysis is only valid for basic
1405 block indices less than bypass_last_basic_block. */
1407 static int bypass_last_basic_block;
1409 /* Find a set of REGNO to a constant that is available at the end of basic
1410 block BB. Return NULL if no such set is found. Based heavily upon
1413 static struct expr *
1414 find_bypass_set (int regno, int bb)
1416 struct expr *result = 0;
1421 struct expr *set = lookup_set (regno, &set_hash_table);
1425 if (TEST_BIT (cprop_avout[bb], set->bitmap_index))
1427 set = next_set (regno, set);
1434 if (cprop_constant_p (src))
1440 regno = REGNO (src);
1445 /* Subroutine of bypass_block that checks whether a pseudo is killed by
1446 any of the instructions inserted on an edge. Jump bypassing places
1447 condition code setters on CFG edges using insert_insn_on_edge. This
1448 function is required to check that our data flow analysis is still
1449 valid prior to commit_edge_insertions. */
1452 reg_killed_on_edge (const_rtx reg, const_edge e)
1456 for (insn = e->insns.r; insn; insn = NEXT_INSN (insn))
1457 if (INSN_P (insn) && reg_set_p (reg, insn))
1463 /* Subroutine of bypass_conditional_jumps that attempts to bypass the given
1464 basic block BB which has more than one predecessor. If not NULL, SETCC
1465 is the first instruction of BB, which is immediately followed by JUMP_INSN
1466 JUMP. Otherwise, SETCC is NULL, and JUMP is the first insn of BB.
1467 Returns nonzero if a change was made.
1469 During the jump bypassing pass, we may place copies of SETCC instructions
1470 on CFG edges. The following routine must be careful to pay attention to
1471 these inserted insns when performing its transformations. */
1474 bypass_block (basic_block bb, rtx setcc, rtx jump)
1479 int may_be_loop_header;
1484 insn = (setcc != NULL) ? setcc : jump;
1486 /* Determine set of register uses in INSN. */
1488 note_uses (&PATTERN (insn), find_used_regs, NULL);
1489 note = find_reg_equal_equiv_note (insn);
1491 find_used_regs (&XEXP (note, 0), NULL);
1493 may_be_loop_header = false;
1494 FOR_EACH_EDGE (e, ei, bb->preds)
1495 if (e->flags & EDGE_DFS_BACK)
1497 may_be_loop_header = true;
1502 for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
1506 if (e->flags & EDGE_COMPLEX)
1512 /* We can't redirect edges from new basic blocks. */
1513 if (e->src->index >= bypass_last_basic_block)
1519 /* The irreducible loops created by redirecting of edges entering the
1520 loop from outside would decrease effectiveness of some of the
1521 following optimizations, so prevent this. */
1522 if (may_be_loop_header
1523 && !(e->flags & EDGE_DFS_BACK))
1529 for (i = 0; i < reg_use_count; i++)
1531 rtx reg_used = reg_use_table[i];
1532 unsigned int regno = REGNO (reg_used);
1533 basic_block dest, old_dest;
1537 set = find_bypass_set (regno, e->src->index);
1542 /* Check the data flow is valid after edge insertions. */
1543 if (e->insns.r && reg_killed_on_edge (reg_used, e))
1546 src = SET_SRC (pc_set (jump));
1549 src = simplify_replace_rtx (src,
1550 SET_DEST (PATTERN (setcc)),
1551 SET_SRC (PATTERN (setcc)));
1553 new_rtx = simplify_replace_rtx (src, reg_used, set->src);
1555 /* Jump bypassing may have already placed instructions on
1556 edges of the CFG. We can't bypass an outgoing edge that
1557 has instructions associated with it, as these insns won't
1558 get executed if the incoming edge is redirected. */
1559 if (new_rtx == pc_rtx)
1561 edest = FALLTHRU_EDGE (bb);
1562 dest = edest->insns.r ? NULL : edest->dest;
1564 else if (GET_CODE (new_rtx) == LABEL_REF)
1566 dest = BLOCK_FOR_INSN (XEXP (new_rtx, 0));
1567 /* Don't bypass edges containing instructions. */
1568 edest = find_edge (bb, dest);
1569 if (edest && edest->insns.r)
1575 /* Avoid unification of the edge with other edges from original
1576 branch. We would end up emitting the instruction on "both"
1578 if (dest && setcc && !CC0_P (SET_DEST (PATTERN (setcc)))
1579 && find_edge (e->src, dest))
1585 && dest != EXIT_BLOCK_PTR)
1587 redirect_edge_and_branch_force (e, dest);
1589 /* Copy the register setter to the redirected edge.
1590 Don't copy CC0 setters, as CC0 is dead after jump. */
1593 rtx pat = PATTERN (setcc);
1594 if (!CC0_P (SET_DEST (pat)))
1595 insert_insn_on_edge (copy_insn (pat), e);
1598 if (dump_file != NULL)
1600 fprintf (dump_file, "JUMP-BYPASS: Proved reg %d "
1601 "in jump_insn %d equals constant ",
1602 regno, INSN_UID (jump));
1603 print_rtl (dump_file, set->src);
1604 fprintf (dump_file, "\nBypass edge from %d->%d to %d\n",
1605 e->src->index, old_dest->index, dest->index);
1618 /* Find basic blocks with more than one predecessor that only contain a
1619 single conditional jump. If the result of the comparison is known at
1620 compile-time from any incoming edge, redirect that edge to the
1621 appropriate target. Return nonzero if a change was made.
1623 This function is now mis-named, because we also handle indirect jumps. */
1626 bypass_conditional_jumps (void)
1634 /* Note we start at block 1. */
1635 if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
1638 bypass_last_basic_block = last_basic_block;
1639 mark_dfs_back_edges ();
1642 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb,
1643 EXIT_BLOCK_PTR, next_bb)
1645 /* Check for more than one predecessor. */
1646 if (!single_pred_p (bb))
1649 FOR_BB_INSNS (bb, insn)
1650 if (DEBUG_INSN_P (insn))
1652 else if (NONJUMP_INSN_P (insn))
1656 if (GET_CODE (PATTERN (insn)) != SET)
1659 dest = SET_DEST (PATTERN (insn));
1660 if (REG_P (dest) || CC0_P (dest))
1665 else if (JUMP_P (insn))
1667 if ((any_condjump_p (insn) || computed_jump_p (insn))
1668 && onlyjump_p (insn))
1669 changed |= bypass_block (bb, setcc, insn);
1672 else if (INSN_P (insn))
1677 /* If we bypassed any register setting insns, we inserted a
1678 copy on the redirected edge. These need to be committed. */
1680 commit_edge_insertions ();
1685 /* Return true if the graph is too expensive to optimize. PASS is the
1686 optimization about to be performed. */
1689 is_too_expensive (const char *pass)
1691 /* Trying to perform global optimizations on flow graphs which have
1692 a high connectivity will take a long time and is unlikely to be
1693 particularly useful.
1695 In normal circumstances a cfg should have about twice as many
1696 edges as blocks. But we do not want to punish small functions
1697 which have a couple switch statements. Rather than simply
1698 threshold the number of blocks, uses something with a more
1699 graceful degradation. */
1700 if (n_edges > 20000 + n_basic_blocks * 4)
1702 warning (OPT_Wdisabled_optimization,
1703 "%s: %d basic blocks and %d edges/basic block",
1704 pass, n_basic_blocks, n_edges / n_basic_blocks);
1709 /* If allocating memory for the cprop bitmap would take up too much
1710 storage it's better just to disable the optimization. */
1712 * SBITMAP_SET_SIZE (max_reg_num ())
1713 * sizeof (SBITMAP_ELT_TYPE)) > MAX_GCSE_MEMORY)
1715 warning (OPT_Wdisabled_optimization,
1716 "%s: %d basic blocks and %d registers",
1717 pass, n_basic_blocks, max_reg_num ());
1725 /* Main function for the CPROP pass. */
1728 one_cprop_pass (void)
1732 /* Return if there's nothing to do, or it is too expensive. */
1733 if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1
1734 || is_too_expensive (_ ("const/copy propagation disabled")))
1737 global_const_prop_count = local_const_prop_count = 0;
1738 global_copy_prop_count = local_copy_prop_count = 0;
1741 gcc_obstack_init (&cprop_obstack);
1743 /* Do a local const/copy propagation pass first. The global pass
1744 only handles global opportunities.
1745 If the local pass changes something, remove any unreachable blocks
1746 because the CPROP global dataflow analysis may get into infinite
1747 loops for CFGs with unreachable blocks.
1749 FIXME: This local pass should not be necessary after CSE (but for
1750 some reason it still is). It is also (proven) not necessary
1751 to run the local pass right after FWPWOP.
1753 FIXME: The global analysis would not get into infinite loops if it
1754 would use the DF solver (via df_simple_dataflow) instead of
1755 the solver implemented in this file. */
1756 changed |= local_cprop_pass ();
1758 delete_unreachable_blocks ();
1760 /* Determine implicit sets. This may change the CFG (split critical
1761 edges if that exposes an implicit set).
1762 Note that find_implicit_sets() does not rely on up-to-date DF caches
1763 so that we do not have to re-run df_analyze() even if local CPROP
1765 ??? This could run earlier so that any uncovered implicit sets
1766 sets could be exploited in local_cprop_pass() also. Later. */
1767 changed |= find_implicit_sets ();
1769 /* If local_cprop_pass() or find_implicit_sets() changed something,
1770 run df_analyze() to bring all insn caches up-to-date, and to take
1771 new basic blocks from edge splitting on the DF radar.
1772 NB: This also runs the fast DCE pass, because execute_rtl_cprop
1773 sets DF_LR_RUN_DCE. */
1777 alloc_hash_table (&set_hash_table);
1778 compute_hash_table (&set_hash_table);
1780 /* Free implicit_sets before peak usage. */
1781 free (implicit_sets);
1782 implicit_sets = NULL;
1785 dump_hash_table (dump_file, "SET", &set_hash_table);
1786 if (set_hash_table.n_elems > 0)
1791 alloc_cprop_mem (last_basic_block, set_hash_table.n_elems);
1792 compute_cprop_data ();
1794 /* Allocate vars to track sets of regs. */
1795 reg_set_bitmap = ALLOC_REG_SET (NULL);
1797 FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR,
1800 /* Reset tables used to keep track of what's still valid [since
1801 the start of the block]. */
1802 reset_opr_set_tables ();
1804 FOR_BB_INSNS (bb, insn)
1807 changed |= cprop_insn (insn);
1809 /* Keep track of everything modified by this insn. */
1810 /* ??? Need to be careful w.r.t. mods done to INSN.
1811 Don't call mark_oprs_set if we turned the
1812 insn into a NOTE, or deleted the insn. */
1813 if (! NOTE_P (insn) && ! INSN_DELETED_P (insn))
1814 mark_oprs_set (insn);
1818 changed |= bypass_conditional_jumps ();
1820 FREE_REG_SET (reg_set_bitmap);
1824 free_hash_table (&set_hash_table);
1825 obstack_free (&cprop_obstack, NULL);
1829 fprintf (dump_file, "CPROP of %s, %d basic blocks, %d bytes needed, ",
1830 current_function_name (), n_basic_blocks, bytes_used);
1831 fprintf (dump_file, "%d local const props, %d local copy props, ",
1832 local_const_prop_count, local_copy_prop_count);
1833 fprintf (dump_file, "%d global const props, %d global copy props\n\n",
1834 global_const_prop_count, global_copy_prop_count);
1840 /* All the passes implemented in this file. Each pass has its
1841 own gate and execute function, and at the end of the file a
1842 pass definition for passes.c.
1844 We do not construct an accurate cfg in functions which call
1845 setjmp, so none of these passes runs if the function calls
1847 FIXME: Should just handle setjmp via REG_SETJMP notes. */
1850 gate_rtl_cprop (void)
1852 return optimize > 0 && flag_gcse
1853 && !cfun->calls_setjmp
1858 execute_rtl_cprop (void)
1861 delete_unreachable_blocks ();
1862 df_set_flags (DF_LR_RUN_DCE);
1864 changed = one_cprop_pass ();
1865 flag_rerun_cse_after_global_opts |= changed;
1871 struct rtl_opt_pass pass_rtl_cprop =
1876 gate_rtl_cprop, /* gate */
1877 execute_rtl_cprop, /* execute */
1880 0, /* static_pass_number */
1881 TV_CPROP, /* tv_id */
1882 PROP_cfglayout, /* properties_required */
1883 0, /* properties_provided */
1884 0, /* properties_destroyed */
1885 0, /* todo_flags_start */
1886 TODO_df_finish | TODO_verify_rtl_sharing |
1887 TODO_verify_flow | TODO_ggc_collect /* todo_flags_finish */